This invention relates to novel antiviral compounds and, more particularly, to O-acylated derivatives of 1,5-dideoxy-1,5-imino-D-glucitol and their N-alkyl, N-acyl and N-aroyl derivatives. These compounds are inhibitors of visna virus, a pathogenic virus for sheep and goats. These antiviral compounds also have potential use for the treatement of acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC).
Acquired immune deficiency syndrome, which only a few years ago was a medical curiosity, is now a serious disease. As a consequence, a great effort is being made to develop drugs and vaccines to combat AIDS. The AIDS virus, first identified in 1983, has been described by several names. It is the third known T-lymphocyte virus (HTLV-III) and has the capacity to replicate within cells of the immune system and thereby lead to a profound destruction of T4.sup.+ T-cells (or CD4.sup.+ cells). See, e.g., Gallo et al., Science 224, 500-503 (1984), and Popovic et al. , Ibid. , 497-500 (1984) . This retrovirus has been known as lymphadenopathy-associated virus (LAV) or AIDS-related virus (ARV) and, most recently, as human immunodeficiency virus (HIV). Two distinct AIDS viruses, HIV-1 and HIV-2, have been described. HIV-1 is the virus originally identified in 1983 by Montagnier and co-workers at the Pasteur Institute in Paris [Ann. Virol. Inst. Pasteur 135 E, 119-134 (1984)], while HIV-2 was more recently isolated by Montagnier and his coworkers in 1986 [Nature 326, 662-669 (1987)]. As used herein, HIV is meant to refer to these viruses in a generic sense.
Although the molecular biology of AIDS is beginning to be unraveled and defined, much more needs to be learned and understood about this disease. In the meantime, numerous approaches are being investigated in the search for potential anti-AIDS drugs and vaccines. Development of an AIDS vaccine is hampered by lack of understanding of mechanisms of protective immunity against HIV, the magnitude of genetic variation of the virus, and the lack of effective animal models for HIV infection. See, for example, Koff and Hoth, Science 241, 426-432 (1988).
The first drug to be approved by the U.S. Food and Drug Administration (FDA) for treatment of AIDS was zidovudine, better known under its former name, azidothymidine (AZT). Chemically, this drug is 3'-azido-3'-deoxythymidine. This drug was originally selected as a potential weapon against AIDS because it was shown to inhibit replication of the virus in vitro. Such in vitro tests are useful and virtually the only practical method of initially screening and testing potential anti-AIDS drugs. A serious drawback of AZT, however, is its toxic side-effects. Thus, the search for better anti-AIDS drugs continues.
The HIV inhibitory activity of 1,5-dideoxy-1,5-imino-D-glucitol (deoxynojirimycin) and its N-methyl derivative is disclosed in PCT Inter. Appln. 87/03903, published Jul. 2, 1987. The substantially more effective anti-HIV activity of the N-butyl derivative of deoxynojirimycin is disclosed in U.S. Pat. No. 4,849,430. Other N-substituted derivatives of deoxynojirimycin having anti-HIV activity are described in EP Applns. 344,383 and 345,104, published Dec. 6, 1989, and EP Appln. 350,012, published Jan. 10, 1990.
U.S. Pat. Nos. 4,182,767 and 4,639,436 show the syntheses and antihyperglycemic use of N-alkyl derivatives of deoxynojirimycin. These patents suggest the use of acyl blocking groups or hydroxyl-protective groups in the syntheses of the desired antihyperglycemic products. However, these blocking groups are proposed only for the preparation of the intermediates and are removed with no isolation or characterization of compounds for antiviral use.